CN111712432B

CN111712432B - Power system of ship

Info

Publication number: CN111712432B
Application number: CN201880089263.0A
Authority: CN
Inventors: 长井秀夫; 时任朋也; 高桥秀幸; 高桥奈津美; 藤野拓哉
Original assignee: Ihi Prime Mover
Current assignee: Ihi Prime Mover
Priority date: 2018-03-13
Filing date: 2018-03-13
Publication date: 2022-04-08
Anticipated expiration: 2038-03-13
Also published as: JPWO2019175951A1; JP7075988B2; WO2019175951A1; SG11202008472YA; CN111712432A

Abstract

A dual fuel engine (3) which can be used with a gas engine and a diesel engine as main fuels includes: a first propulsion device (5A) connected to and driven by an engine (3A) via a first clutch (9A); and a propulsion device-side output sensor (14A) provided between the engine (3A) and the first clutch (9A). The method comprises the following steps: a fire fighting device (6) having a fire extinguishing pump (11) connected to and driven by an engine (3A) via a second clutch (18); and a work device side output sensor (19) provided to the engine (3A) and the second clutch (18). Further comprising: a second propulsion device (5B) that is connected to and driven by another engine (3B) via a first clutch (9B); and a propulsion device-side output sensor (14B) provided between the engine (3B) and the first clutch (9A).

Description

Power system of ship

Technical Field

The present invention relates to a power system for a ship, which includes an engine that uses both a gaseous fuel and a liquid fuel as main fuels, and is equipped with an engine that is a propulsion device, and which can use the output of the engine for a work device other than propulsion.

Background

As an example of the power system of the ship, a power system of a working ship on which the fire fighting device described in patent document 1 is mounted has been proposed. The power plant described in patent document 1 is a power plant using a diesel engine as a main machine. In the power plant of this work vessel, power is extracted to a propeller shaft system having a main machine such as a diesel engine and to which a propeller of the work vessel is connected through a wheel, and a fire fighting device that drives a fire pump provided as an auxiliary machine to eject seawater is provided.

In the fire fighting operation, the power system detects the overload of the main machine through the load detection device, and reduces the wing angle of the propelling machine so as to restrain the overload of the main machine. When the fire pump is stopped, a clutch provided in the pump drive shaft system is disengaged from power of the main engine to prevent transmission of power.

On the other hand, from the viewpoint of reduction of exhaust gas and environmental protection, attempts have been made to use a gas engine that can be used mainly with a gaseous fuel as a main fuel, instead of a diesel engine that uses a liquid fuel as a main fuel. The gas engine is mainly used as a main engine of a large ship such as an LNG ship or a tanker, and can be operated only in a range where the ratio of the air-fuel ratio that can be burned is narrow, and therefore it is difficult to quickly cope with a sudden load variation. Therefore, the present invention is not applicable to a work ship including a work equipment such as a fire fighting equipment, and the power plant of the work ship described in patent document 1 extracts power from a diesel engine as a power source.

Documents of the prior art

Patent document

Patent document 1: japanese Kokoku publication Sho 62-23359

Disclosure of Invention

Technical problem to be solved by the invention

However, in recent years, the emission limits of air pollutants emitted from ships, which are at the heart of international regulations, have become more stringent. For example, in the sea area called a part of ECA, emission of sulfur oxides and nitrogen oxides is more strictly limited.

However, the power plant of the work ship described in patent document 1 does not sufficiently meet the above-mentioned emission limit requirements for air pollutants, since it uses a diesel engine as a main engine.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a power system for a ship, which uses a gas fuel as a main fuel and can perform strict combustion control by using the gas fuel as a drive source for a working device as well as a drive source for a propulsion device to cope with load fluctuations.

Another object of the present invention is to provide a power system for a ship, which uses a gas fuel as a main fuel and can quickly cope with a sudden load change or a large load change to drive a working device.

Means for solving the problems

The power system of a ship according to the present invention is characterized by comprising: an engine capable of using a gaseous fuel as a main fuel; a propulsion device connected to the engine via a first clutch and driven; a propulsion unit-side output sensor provided between the engine and the first clutch; a working device connected to and driven by the engine via a second clutch; and a working device side output sensor provided between the engine and the second clutch.

According to the present invention, the first clutch is closed and the second clutch is opened to drive the propulsion device, and the output of the engine that drives the propulsion device is measured by the propulsion device-side output sensor. The working device is driven by opening the first clutch and closing the second clutch, and the output of an engine that drives the working device is measured by a working device side output sensor. In an engine using a gaseous fuel, since a gas serving as a fuel is an elastic body, it is relatively difficult to obtain an accurate fuel supply amount compared to a liquid fuel, and therefore an actual engine output is measured by an output sensor, and the engine is controlled based on the measured value. With the propulsion device-side output sensor and the working device-side output sensor, the actual output of the engine including the loss due to the resistance of the transmission system, the clutch, and the like can be accurately measured in both the case of driving the propulsion device and the case of driving the working device, and the engine using gaseous fuel as the main fuel can be strictly controlled.

Further, the working device is a fire fighting device for spraying water.

The working device side output sensor can accurately measure the actual output of the engine when the fire fighting device is driven, and the engine can be strictly driven and controlled.

Further, the present invention is characterized by comprising a control device that closes the first clutch and opens the second clutch to drive the propulsion device, and opens the first clutch and closes the second clutch to drive the working device.

According to the control device, the driving of the propulsion device and the driving of the working device can be switched by switching the opening and closing of the first clutch and the second clutch.

Preferably, the engine is controlled based on a sum of an output measurement value based on the propulsion device-side output sensor and an output measurement value based on the work device-side output sensor.

By obtaining the sum of the output measurement value by the propulsion device-side output sensor and the output measurement value by the work device-side output sensor, a more accurate output value of the engine can be obtained. For example, while most of the engine output is measured by the propulsion unit-side output sensor in a state where the propulsion unit is being driven, the work unit-side output sensor also shows a certain level of output value due to the traction resistance of the clutch in the open state and the mechanical loss. Therefore, by obtaining the sum of the output values of the output sensors based on both, a more accurate output value of the engine can be measured.

Preferably, the control unit performs the control to reduce the rotation speed of the engine when the output measurement value of the propulsion device-side output sensor and/or the output measurement value of the work device-side output sensor exceeds the upper limit value.

In operation in an operation mode (also referred to as a "gas mode") in which gas fuel is the main fuel, when the output value of the propulsion device-side output sensor or the output value of the working device-side output sensor exceeds the upper limit value for a predetermined time, automatic deceleration control is performed to forcibly reduce the engine speed. In the operation in the gas mode, since knocking and misfire are likely to occur when the output of the engine becomes excessive, when the output value of the output sensor exceeds the upper limit value, the output of the engine is reduced by forcibly performing control to reduce the rotation speed, thereby preventing knocking, misfire, and the like.

As the upper limit value, either or both of an upper limit value of the power output from the engine and an upper limit value of the torque may be used. In addition, the torque may be set to an upper limit value that varies depending on the rotation speed of the engine, as well as a single upper limit value.

Preferably, the propulsion device-side output sensor and the working device-side output sensor are torque sensors that measure torque actually applied to a propulsion shaft of the engine.

Torque sensors are used as a propeller-side output sensor and a work-device-side output sensor, and the torque actually applied to the propeller shaft of the engine is measured. The output (power) of the engine can be obtained by multiplying the torque value obtained by the torque sensor by the engine speed obtained by the engine speed sensor.

In the power system for a ship according to the present invention, when the operation mode is switched from the state in which the propulsion device is driven to the state in which the working device is driven in the operation mode in which gaseous fuel is used as the main fuel, the operation mode is temporarily switched from the operation mode in which gaseous fuel is used as the main fuel to the operation mode in which liquid fuel is used as the main fuel (also referred to as "diesel mode"), and at least one of the first clutch and the second clutch is operated, and then the operation mode is returned from the operation mode in which liquid fuel is used as the main fuel to the operation mode in which gaseous fuel is used as the main fuel.

According to the present invention, in the operation in the mode using the gaseous fuel as the main fuel, when the propulsion device is driven to the working device, the operation mode of the gaseous fuel is temporarily switched to the operation mode of the liquid fuel, and the opening and closing operations of the first clutch and the second clutch are performed. The operation mode of the engine based on the gaseous fuel is easily affected by the load fluctuation, and there is a possibility that the smooth operation of the engine is hindered by the disturbance caused by the opening and closing of each clutch.

In the power system for a ship according to the present invention, when the operation mode is switched from the state in which the working device is driven to the state in which the propulsion device is driven during the operation in the operation mode in which gaseous fuel is used as the main fuel, the operation mode is switched from the operation mode in which gaseous fuel is used as the main fuel to the operation mode in which liquid fuel is used as the main fuel, and at least one of the second clutch and the first clutch is operated, and then the operation mode is returned from the operation mode in which liquid fuel is used as the main fuel to the operation mode in which gaseous fuel is used as the main fuel.

In the present invention, during operation in the mode using gaseous fuel as the main fuel, when the state of driving the working device is returned to the state of driving the propulsion device, the mode is temporarily switched to the diesel mode using liquid fuel as the main fuel, and the opening and closing operations of the first clutch and the second clutch are performed in the diesel mode. Since the first clutch is closed to the propulsion device side with relatively large disturbance, the first clutch can be closed by switching to the diesel mode, and a stable switching operation can be performed without being affected by the load fluctuation.

Further, the control device preferably includes: a diesel mode switching means for switching from a gas mode in which gas fuel is the main fuel to a diesel mode in which liquid fuel is the main fuel, in order to perform an operation of opening one of the first clutch and the second clutch and closing the other; and a gas mode switching unit which switches from the diesel mode to the gas mode after the action of opening one of the first clutch and the second clutch and closing the other clutch is finished.

Since the engine is likely to be affected by load fluctuations in the operation mode of the engine using gaseous fuel and smooth operation of the engine may be hindered by interference caused by opening and closing of the first clutch and the second clutch, the opening and closing operations of the first clutch and the second clutch are performed by temporarily shifting to the diesel mode resistant to load fluctuations, and stable switching operation can be performed without being affected by load fluctuations. After that, the operation in which the adverse effect on the environment is reduced can be realized by shifting to the gas mode.

Further, a power system for a ship according to the present invention includes a plurality of engines that can use both a gaseous fuel and a liquid fuel as main fuels, and is characterized by including, on one engine side: a propulsion device connected to the engine via a first clutch and driven; a propulsion unit-side output sensor provided between the engine and the first clutch; a working device connected to and driven by the engine via a second clutch; a working device side output sensor provided between the engine and the second clutch; and a control device that closes the first clutch and opens the second clutch to drive the propulsion device, opens the first clutch and closes the second clutch to drive the working device, and includes, on the other engine side: another propulsion device connected to another engine via a third clutch and driven; and another propulsion device side output sensor provided between the another engine and the third clutch, and configured to drive the another propulsion device by closing the third clutch by the control device.

According to the present invention, when the working device is driven by one engine, the other propulsion device is propelled by the other engine based on the other propulsion device side output sensor, whereby the propulsion of the ship can be continued. In particular, in the case where a fire fighting apparatus for spraying water is provided as a working apparatus, a reaction force due to the water spray is generated, but the reaction force is offset by continuing the propulsion of the ship, so that the water spray work can be performed in a stable state.

Effects of the invention

According to the power system for a ship according to the present invention, since the propulsion-device-side output sensor is provided between the engine and the first clutch and the working-device-side output sensor is provided between the engine and the second clutch in the propulsion shaft of the engine that can be operated using gaseous fuel as a main fuel, the output value of the engine is detected and controlled by the respective sensors, and it is possible to drive not only the propulsion device but also the working device.

Further, the output actually output from the engine including the loss due to the resistance of the transmission system, the clutch, and the like can be measured more accurately, and the output including the resistance can be measured even in a state where each clutch is opened.

Drawings

Fig. 1 is an explanatory view showing the overall structure of a ship including a fire fighting device of an embodiment of the present invention.

Fig. 2 is an explanatory diagram showing the structures of an engine, a propulsion device, and a fire fighting device in a ship according to an embodiment.

Fig. 3 is an explanatory diagram showing the overall structure of the engine shown in fig. 2.

Fig. 4A is an explanatory diagram showing the diesel mode engine.

Fig. 4B is an explanatory diagram showing the gas mode engine.

Fig. 5 is a flowchart showing a procedure of switching from the drive of the propulsion device to the drive of the fire fighting device in the first embodiment.

Fig. 6 is a flowchart showing a procedure of switching from the drive of the fire fighting device to the drive of the propulsion device.

Fig. 7 is a flowchart showing a procedure of switching from the drive of the fire fighting device to the drive of the propulsion device in the second embodiment.

Fig. 8 is a flowchart showing control of automatic deceleration.

Detailed Description

Hereinafter, a power system of a ship 1 according to an embodiment of the present invention will be described with reference to fig. 1 to 8.

A ship 1 shown in fig. 1 is a ship showing a basic structure of a ship propulsion device of a working ship such as a tugboat. The ship 1 includes a dual-fuel engine 3 as an engine as a main engine, and can be operated in two modes, i.e., a gas mode in which a gas fuel is used as a main fuel and a diesel mode in which a liquid fuel is used as a main fuel, by switching between the two modes.

In the ship 1, the engine serving as a main engine can switch the transmission direction of the driving force of the dual-fuel engine 3, and the propulsion device 5 including the propeller 5a and the fire fighting device 6 capable of spraying seawater drawn from the sea by the water spray nozzle 6a can be selectively driven.

The ship 1 shown in fig. 1 has, for example, an azimuth thruster (clutch-independent azimuth thruster) 8 as a propulsion device for the ship. Note that the vessel 1 according to the present embodiment may not be provided with the azimuth thruster 8.

In the marine vessel 1 shown in fig. 1, a first clutch 9 serving as a main clutch is provided between the driven rear end side of the dual-fuel engine 3 serving as a main engine and the azimuth thruster 8. A propulsion device 5 including a propeller 5a is connected to the rear end side of the azimuth thruster 8. The first clutch 9 is a slip clutch, and performs slip control to reduce the maximum rotation speed of the dual-fuel engine 3 to a desired rotation speed to drive the propeller 5a of the propulsion device 5.

The speed increasing gear 10 may be connected to the fire fighting device 6 provided on the front end side of the dual-fuel engine 3. Seawater is discharged from the water discharge nozzle 6a by a fire pump 11 provided in the fire fighting device 6.

Next, the structure of the ship propulsion device of the ship 1 shown in fig. 1 will be described in more detail with reference to fig. 2. The same basic configuration as that of the ship propulsion device of the ship 1 shown in fig. 1 will be described based on a specific arrangement configuration shown in fig. 2. In fig. 2, a specific configuration will be described by adding A, B to the same reference numeral for a configuration in which each of the components of the ship 1 shown in fig. 1 is paired.

In the ship 1 shown in fig. 2, for example, two dual-fuel engines (hereinafter, may be simply referred to as "engines") 3 are provided in parallel, one of which is a dual-fuel engine 3A, and the other is a dual-fuel engine 3B. The

dual fuel engines

3A, 3B each include an ECU. The propulsion mechanism including the dual-fuel engine 3A on the port side is referred to as a first marine propulsion device 20A, and the propulsion mechanism including the dual-fuel engine 3B on the starboard side is referred to as a second marine propulsion device 20B.

In the vessel 1, a tugboat and a work boat having a fire-fighting function are often configured such that two

engines

3A and 3B are provided in parallel on both the right and left sides. Thus, when the fire pump 11 of the fire fighting device 6 is driven by one of the dual-fuel engines 3A to discharge seawater, the other dual-fuel engine 3B propels the fire, thereby preventing the ship 1 from moving backward by the reaction force of the driving load of the fire pump 11, and enabling fire extinguishing activities.

In the first ship propulsion device 20A on the port side, the propulsion device 5A is provided on the propulsion shaft 13A provided in the dual-fuel engine 3A via the first clutch 9A as the main clutch. The first clutch 9A is a slip clutch, and can be switched so as to freely change the load transmission rate within a range of a slip rate of 100% to 0%. The propeller shaft 13A is connected to a propeller 5A having a propeller 5A.

A propulsion device side output sensor 14A is provided between the dual-fuel engine 3A and the first clutch 9A. A rotation speed sensor 15A that detects the rotation speed of the propeller shaft 13A is provided between the dual-fuel engine 3A and the propeller-side output sensor 14A. The propulsion unit-side output sensor 14A is a torque sensor that detects torque, and can calculate an output by multiplying the torque by the rotation speed measured by the rotation speed sensor 15A. The propulsion unit-side output sensor 14A may detect both the rotation speed and the torque.

A fire pump 11 of the fire fighting device 6 is connected to a drive shaft 17 provided on the opposite side of the propulsion device 5A with respect to the dual-fuel engine 3A, and a second clutch 18 is attached to the fire pump 11 on the dual-fuel engine 3A side. The second clutch 18 is a PTO (power take off) clutch.

A working device side output sensor 19 is provided between the second clutch 18 and the dual-fuel engine 3A. The work device side output sensor 19 is also a torque sensor that detects torque, as with the propulsion device side output sensor 14A, and can calculate an output by multiplying the torque by the rotation speed measured by the rotation speed sensor 15A. The work implement side output sensor 19 may detect both the rotation speed and the torque.

These respective components of the port-side first marine propulsion device 20A are electrically connected to the control device 22. When the propulsion device 5A is driven, the control device 22 closes the first clutch 9A and opens the second clutch 18 on the fire fighting device 6 side, and when the fire fighting device 6 is driven, opens the first clutch 9A and closes the second clutch 18 on the fire fighting device 6 side. When the propulsion device 5A or the fire fighting device 6 is driven, the control device 22 controls the operation of the bi-fuel engine 3A based on the output value of the bi-fuel engine 3A measured by the rotation speed sensor 15A and the propulsion device side output sensor 14A or the working device side output sensor 19.

In the second marine propulsion device 20B on the starboard side shown in fig. 2, the propulsion device 5B is provided on the propulsion shaft 13B provided in the dual-fuel engine 3B via the third clutch 9B as the main clutch. The third clutch 9B is a slip clutch similar to the first clutch 9A, and can switch the load transmission rate change. The propeller shaft 13B is connected to a propeller 5B having a propeller 5B.

A propulsion device side output sensor 14B is provided between the dual-fuel engine 3B and the third clutch 9B. A rotation speed sensor 15B is provided between the dual-fuel engine 3B and the propulsion device side output sensor 14B. The propulsion unit-side output sensor 14B is a torque sensor that detects torque, and can calculate an output by multiplying the torque by the rotation speed measured by the rotation speed sensor 15B. The propulsion unit-side output sensor 14B may detect both the rotation speed and the torque.

These respective components of the second marine propulsion device 20B on the starboard side are electrically connected to the control device 22, respectively, in the same manner as the first marine propulsion device 20A. When the propulsion device 5B is driven, the control device 22 closes the third clutch 9B. Then, the operation of the bi-fuel engine 3B is controlled by the control device 22 based on the output value of the bi-fuel engine 3B measured by the rotation speed sensor 15B and the propulsion device side output sensor 14B.

Next, the structure and function of the dual fuel engine 3 will be described as a four-stroke engine, for example, with reference to fig. 3, 4A, and 4B.

The dual fuel engine for a ship (hereinafter, may be simply referred to as an engine) 3 shown in fig. 3, 4A, and 4B can be switched to either a diesel mode or a gas mode during operation. The dual fuel engine 3 shown in fig. 3 includes a mechanism of a crankshaft 24 as

propulsion shafts

13A and 13B coupled to

propellers

5a and 5B, and the crankshaft 24 is coupled to a piston 26 provided in a cylinder 25. A combustion chamber 28 is formed by a piston 26 provided in the cylinder block 25 and an engine head 27.

The combustion chamber 28 is closed by an intake valve 29, an exhaust valve 30, and a fuel injection valve 31 used in the diesel mode, which are mounted to the engine head 27. The engine head 27 is provided with a micro pilot injection valve 32 used in the gas mode. A fuel injection pump 33 is connected to the fuel injection valve 31. An intake pipe 34 is connected to an intake port of the engine head 27 provided with the intake valve 29, and an exhaust pipe 35 is provided to an exhaust port provided with the exhaust valve 30. A fuel gas supply valve 36 including an electromagnetic valve that controls gas injection is provided in the intake pipe 34, and an air cooler 37 and a supercharger 38 that communicates with the exhaust pipe 35 are provided on the upstream side of the fuel gas supply valve 36.

As shown in fig. 4A and 4B, the dual-fuel engine 3 according to the present embodiment can be switched to either a diesel mode or a gas mode to operate. In the diesel mode shown in fig. 4A, for example, heavy oil a or the like is supplied as fuel oil from a fuel tank, not shown, to the fuel injection pump 33, and the fuel oil is mechanically injected from the fuel injection valve 31 into the compressed air in the combustion chamber 28, and is ignited and combusted.

In the gas mode shown in fig. 4B, fuel gas such as natural gas is supplied to the intake pipe 34 by the fuel gas supply valve 36, premixed with the air flow, and the mixture is supplied into the combustion chamber 28, and ignited by the ignition device in a compressed state of the mixture. In this example, pilot fuel is injected from the micro pilot injection valve 32 to be ignited and burned. The micro pilot injection valve 32 is electronically controlled, for example, to inject a small amount of pilot fuel as a powerful ignition source. The fuel gas supply valve 36 is an electromagnetic valve that is opened in a small stroke and can flow a large amount of fuel gas in a short time.

The gas mode includes both an operation system in which ignition is performed by an ignition plug using only gas fuel (gas fuel) as fuel and an operation system in which injection of a small amount of liquid fuel (pilot oil) is used for ignition of most of the gas fuel that occupies a heat source. In general, the proportion of the liquid fuel in the total fuel in the latter operation mode is about 1% to 10% of the total heat quantity in terms of the heat quantity of the rated output. From the viewpoint of completing environmental restriction on the exhaust gas, it is preferably 3% or less.

The diesel mode is mainly used for an operation mode in which the engine is operated using only liquid fuel as fuel during start and stop of the engine, and during load fluctuations such as switching of the opening and closing of the first clutch 9A, the third clutch 9B, and the second clutch 18 when the mode is switched between the normal operation mode and the fire fighting mode.

The engine 3 is started in a diesel mode in which liquid fuel is injected from the fuel injection valve 31 into the combustion chamber 28. After confirming that the gas pressure equal to or higher than the reference value is supplied to the engine 3, the gas fuel is supplied to the intake pipe 34 by the fuel gas supply valve 36, mixed with the air, and flows into the combustion chamber 28, and the operation is performed in the gas mode in which the gas fuel is burned.

The stop is performed after changing to the diesel mode again at the time of the stop. The diesel mode and the gas mode may be changed except at the time of start and stop.

In the steady operation, the engine 3 is theoretically operated in the gas mode along the cubic characteristic line for the ship in accordance with the relationship between the rotation speed and the output. The cubic characteristic for a ship is a characteristic of a ship main engine (engine 3) that outputs an output proportional to the cube of the rotation speed in a ship using a propeller 5a having a fixed pitch. In addition to the smooth operation, when the ship is driven during heavy rain, such as when the ship is sailing or when the ship is changing its course rapidly, the output that greatly exceeds the cubic characteristic for the ship and is equal to or more than the normal operation range is required, and in the gas mode, the liquid fuel is temporarily supplied into the combustion chamber 28 and is operated together with the gas fuel because the output is insufficient and the operation is difficult.

In the operation system of the ship 1 according to the present embodiment, in order to cope with the emission restrictions, the normal operation (normal operation mode) using the propulsion device 5 and the fire extinguishing operation (fire extinguishing mode) using the fire fighting device 6 are basically performed in the gas mode. In such a case, it is difficult to obtain an accurate supply amount of the gas fuel in the gas engine and the magnitude of the output cannot be known, but the propulsion-unit-

side output sensors

14A and 14B and the working-unit-side output sensor 19 are provided in the first marine propulsion unit 20A and the second marine propulsion unit 20B, respectively, to detect the magnitude of the output at appropriate times. As the propulsion device

side output sensors

14A and 14B and the working device side output sensor 19, a spindle dynamometer is preferably used.

In addition, in the load drive based on the gas mode, since the load fluctuation is large when the normal operation mode and the fire mode are switched to each other, the gas mode is temporarily switched to the diesel mode. This makes it possible to quickly cope with the load variation caused by the switching of the opening and closing of the first clutch 9A, the third clutch 9B, and the second clutch 18. Therefore, the control device 22 is provided with a diesel mode transition unit 63, and the diesel mode transition unit 63 detects an instruction signal for fire mode transition and temporarily transitions from the gas mode to the diesel mode. Similarly, a gas mode changeover unit 64 is provided, and the gas mode changeover unit 64 changes from the diesel mode to the gas mode after load fluctuation is leveled out by switching the opening and closing of the first clutch 9A, the third clutch 9B, and the second clutch 18.

When the load fluctuation at the time of transition from the propulsion mode to the fire fighting mode is relatively small, the mode may be changed to the fire fighting mode while maintaining the gas mode without changing to the diesel mode.

In the power system of the ship 1 according to the present embodiment, the total of the output measurement value of the propulsion system-side output sensor 14A by the first ship propulsion system 20A and the output measurement value of the work apparatus-side output sensor 19 may be obtained, so that the more accurate output value of the engine 3A is obtained and the engine 3A may be controlled.

For example, while most of the output of the engine 3A is measured by the propulsion unit-side output sensor 14A in a state where the first marine propulsion unit 20A is driven, a certain level of output value may be counted by the working unit-side output sensor 19. This is because, even in a state where the second clutch 18 on the fire fighting device 6 side is opened, a mechanical loss remains to some extent on the fire fighting device 6 side. When the fire pump 11 of the fire fighting device 6 is driven with the first clutch 9A on, a certain level of output value can be similarly counted by the working device side output sensor 19.

Therefore, by obtaining the sum of the output values from the propulsion device-side output sensor 14A and the work device-side output sensor 19, a more accurate output value of the engine 3A can be obtained.

The dual fuel engine 3 according to the present embodiment includes a gas engine system that performs output control at the time of load increase in the gas mode. The structure of the gas engine system will be explained.

In fig. 3, a rotation speed sensor 15(15A, 15B) and a propulsion-unit-side output sensor 14(14A, 14B) are attached to a crankshaft 24, the rotation speed (rotation speed) of the crankshaft 24 is measured by the rotation speed sensor 15, and the engine torque is measured by the propulsion-unit-side output sensor 14. As the propulsion device side output sensor 14, for example, a strain sensor that detects torque applied to a shaft by strain can be used. The measurement data measured by the rotation speed sensor 15 and the propulsion unit-side output sensor 14 are output to a control unit 22 that controls the engine 3.

The control device 22 detects the operating state of the engine 3 based on signals from the rotation speed sensor 15, the propulsion unit-side output sensor 14, and the like. That is, the output (load) a of the engine 3 is calculated from the following equations (1) and (2) with n being the number of revolutions (rotational speed) of the crankshaft 24 measured by the revolution sensor 15 and T being the torque measured by the propulsion device side output sensor 14. Where Lt is the rated output of the engine 3.

Output Lo 2 pi Tn/60 (1)

Output (load) A Lo/Lt × 100 (2)

As a method of determining the output (load) of the engine 3, there are: a method of estimating the fuel supply amount based on information relating to the operating state of the engine 3; and a method of obtaining an output by providing a propulsion unit side output sensor 14 in a power transmission system of a propeller shaft 13(13A, 13B) of the engine 3 and actually measuring a torque. In a gas fuel engine, since a gas as a fuel is an elastomer, it is relatively difficult to obtain an accurate supply amount of the fuel as compared with a liquid fuel. Therefore, it is preferable that the propulsion unit-side output sensor 14 actually measures the torque and calculates the output.

When the rotation speed n is constant, the output a and the torque measurement value T are in a proportional relationship. Under the condition that the rotation speed n is constant, it is desirable that the timing of the closing of the intake valve 29 is advanced at a larger rate as the output a is larger, that is, as the torque data T is larger.

The control device 22 stores a first map 40 of a first electric signal for specifying the opening/closing timing of the intake valve and a second map 41 of a second electric signal for specifying the opening/closing timing from the first electric signal, which are generated in advance. The control device 22 calculates the output a of the engine 3 by the above equations (1) and (2) based on the rotational speed data n and the torque data T corresponding to the output a of the engine 3 measured by the rotational speed sensor 15 and the propulsion-unit-side output sensor 14. The first electric signal corresponding to the opening and closing timing of the intake valve 29 is selected in the first map 40 by the rotation speed n and the output a. Based on the first electric signal, the opening and closing timing of the intake valve 29 corresponding to the first electric signal is determined in the second map 41.

The second electric signal of the opening/closing timing set by the control device 22 is sent to the electro-pneumatic transducer 42, and the signal of the opening/closing timing is converted into the air pressure by the electro-pneumatic transducer 42. This air pressure is sent to the actuator 43 to control the driving of the variable intake valve timing mechanism 44. The air pressures P1 and P2 for driving and controlling are supplied from the first step-down regulator 45 and the electro-pneumatic converter 42 to the actuator 43.

The air pressure supplied to the actuator 43 is compressed by an air compressor 46 and stored in an air tank 47. The air pressure in the air tank 47 can be reduced to a desired pressure by the first pressure reducing regulator 45. The pressure at this time can be adjusted by changing the valve opening degree of the first pressure reducing regulator 45, and is supplied to the actuator 43 as the air pressure P1 for driving. When the pressure P1 measured by the pressure gauge 48 is equal to or less than a predetermined value, the engine 3 cannot be started.

The air pressure for driving the electric air-fuel converter 42 is supplied from the first step-down regulator 45 after being further stepped down by the second step-down regulator 49. The electro-pneumatic converter 42 supplies the air pressure corresponding to the input second electric signal of the opening/closing timing to the actuator 43 as the air pressure P2 for adjusting the operation of the actuator 43. Based on these air pressures P1, P2, the rod 43a of the actuator 43 is operated to operate the variable intake valve timing mechanism 44.

The actuator 43 is, for example, a known P cylinder (a cylinder with a limit point), and controls the advance and retreat of the rod 43a based on pressures P1, P2 input from the first step-down regulator 45 and the electro-pneumatic converter 42. The compression ratio is controlled to be lowered by changing the moving length of the rod 43a of the actuator 43, controlling the drive of the variable intake valve timing mechanism 44, and advancing (advancing) or retarding (retarding) the timing at which the intake valve 29 is closed from the intake bottom dead center.

Since the time between the valve opening timing and the valve closing timing of the intake valve 29 does not change, when the valve opening timing advances from the intake bottom dead center, the valve closing timing also advances from the intake top dead center by the same time. In the present embodiment, the timing of opening and closing the valve is changed in accordance with the output of the engine 3, whereby knocking is suppressed and the load increase time is shortened. The opening/closing timing of the intake valve 29 is set by the first map 40 and the second map 41 in the control device 22 based on the output a and the rotation speed n of the engine 3, and the opening/closing timing of the intake valve 29 is adjusted by the actuator 43 and the variable intake valve timing mechanism 44 so that knocking can be suppressed.

The structure of the variable intake valve timing mechanism 44 is conventionally known. That is, in the variable intake valve timing mechanism 44, for example, a link shaft that sets a rotational angle range by the movement length of the rod 43a of the actuator 43 is disposed in parallel with a camshaft provided with an eccentric cam. The exhaust rocker arm is connected to the link shaft, and the intake rocker arm is connected to a tappet shaft provided at an eccentric position of the link shaft. The intake valve 29 is connected to an intake rocker arm, and the exhaust valve 30 is connected to an exhaust rocker arm.

The distance between the camshaft and the intake rocker arm changes according to the rotation angle of the tappet shaft corresponding to the rotation of the link shaft, and the timing at which the eccentric cam of the camshaft starts to touch changes. This makes it possible to change the valve closing timing to the advanced angle (or the retarded angle). The closing timing of the intake valve 29 becomes earlier the farther the distance from the tappet shaft to the camshaft center becomes. The rotation angle of the tappet shaft may be changed according to the moving length of the rod 43a of the actuator 43. The moving length of the rod 43a is arbitrarily changed according to the pressures P1, P2 of the control air supplied to the actuator 43.

The magnitude of the advance angle of the intake valve 29 as the opening/closing timing is determined by the timing at which the eccentric cam of the camshaft starts to contact the intake rocker arm coupled to the tappet shaft of the link shaft.

Instead of the actuator 43, a servomotor, not shown, may be used as the lifter shaft rotating device in the variable intake valve timing mechanism 44. In this case, the opening/closing timing signal transmitted from the second map 41 of the control device 22 is input to the servo motor. The servo motor rotates the link shaft by an amount corresponding to the received signal to rotate the tappet shaft, thereby moving the tappet shaft closer to or away from the camshaft, and changing the opening/closing timing of the intake valve 29. When the servo motor is used, the actuator 43 and the structure from the first down-regulator 45 to the pressure gauge 50 are not required. In addition, the servo motor is driven by the controller instead of the electro-pneumatic converter 42.

A supply mechanism for supplying the fuel gas to the fuel gas supply valve 36 that controls the injection of the fuel gas into the intake pipe 34 will be described. In fig. 3, a gas fuel is supplied from an LNG gas tank 52 in which a gas fuel such as natural gas is stored to a gas vaporizer 53, and the gas pressure is reduced to a desired gas pressure by a gas regulator 54.

The gas pressure is indicated by a fuel gas pressure gauge 55, and is adjusted by changing the valve opening of the gas regulator 54, so that the gas fuel for combustion is supplied from the fuel gas supply valve 36 into the intake pipe 34. In the intake pipe 34, the gas fuel is mixed with the supercharged air cooled by the air cooler 37 and supplied to the combustion chamber 28. When the load is increased, the supply amount of the gas fuel is increased by the operation of the fuel gas supply valve 36.

The second electric signal of the opening/closing timing set by the control device 22 is sent to the fuel gas supply valve 36 via a gas governor 57 different from the electro-pneumatic converter 42. The gas governor 57 performs speed regulation control (governor control) of the supply amount of the gas fuel in the gas mode. The gas governor 57 is controlled to advance the valve opening timing for opening the fuel gas supply valve 36 and supplying the gas fuel into the intake pipe 34 in accordance with the advance timing of the timing for closing the intake valve 29. The gas governor 57 is included in the fuel gas supply valve timing mechanism 60, and the gas governor 57 performs speed control by advancing the valve opening timing of the fuel gas regulator 54 for adjusting the gas pressure and the fuel gas supply valve 36.

The gas governor 57 may be provided outside the control device 22. The fuel gas supply valve timing mechanism 60 may be configured to receive the second electric signal from the second map 41 and advance the valve opening timing of the fuel gas supply valve 36 in accordance with the advance of the timing at which the intake valve 29 is closed.

Further, during the operation in the gas mode of the ship 1, when the normal operation mode is changed to the fire protection mode, or when the fire protection mode is changed to the normal operation mode, the gas mode is temporarily switched to the diesel mode, and the opening/closing switching operation of the first clutch 9A and the second clutch 18 is performed in the diesel mode. The engine 3A is likely to be affected by load fluctuations during operation in the gas mode, and smooth operation of the engine 3A may be hindered by interference caused by opening and closing operations of the first clutch 9A and the second clutch 18. Therefore, at the time of transition between the normal operation mode and the fire fighting mode, the gas mode is temporarily changed to the load fluctuation tolerant diesel mode to perform the opening and closing operations of the first clutch 9A and the second clutch 18, thereby making it possible to suppress adverse effects on the engine 3A due to load fluctuations.

In the case where the load due to the fire pump 11 is relatively small, the disturbance when the second clutch 18 on the fire pump 11 side is closed is also relatively small, and therefore, this operation may be omitted depending on the conditions.

In the power system of the ship 1 according to the present embodiment, the normal operation of the ship 1 is performed in the gas mode, and when the normal operation mode is changed from the gas mode to the fire mode, the load may fluctuate rapidly or the load fluctuation may be small. Therefore, in the present embodiment, (a) a case where the diesel mode is used at the time of bidirectional transition between the normal operation and the fire fighting operation is described as a first example, and (B) a case where the gas mode is maintained at the time of transition from the normal operation to the fire fighting operation, and the diesel mode is used only at the time of transition from the fire fighting operation to the normal operation is described as a second example.

(A) First embodiment

The steps of the case of passing through the diesel mode at the time of bidirectional transition between the normal operation mode and the fire fighting mode will be described along the flowchart shown in fig. 5.

In such a case, the load on the fire pump 11 in the fire fighting device 6 is preferably relatively large.

a) And switching from the normal operation mode to the fire fighting mode.

When the dual-

fuel engines

3A, 3B in the ship 1 are operated in the normal mode, the first ship propulsion device 20A and the second ship propulsion device 20B on both the side and the side are operated in the gas mode in which the first clutch 9A and the third clutch 9B are closed and the second clutch 18 is opened (S100). The ship 1 is propelled by driving the port and

starboard propellers

5a, 5 b. In order to switch from this state to the fire fighting mode, the rotation speed of the right and left twin-

side engines

3A, 3B is decelerated to idle operation (S101).

Next, the first clutch 9A and the third clutch 9B on the port and starboard sides are opened. Then, a switching instruction signal for switching to the fire fighting mode is input to the control device 22(S102), and the first marine propulsion device 20A on the port side is switched from the gas mode operation to the diesel mode operation (S103). Thereafter, the third clutch 9B of the second marine propulsion device 20B on the starboard side is closed, and the second clutch 18 of the fire fighting device 6 on the port side is closed (S104).

The operation of the engine 3A in the gas mode is easily affected by the load variation, and there is a possibility that the smooth operation of the engine 3A is hindered by the interference caused by the opening and closing operations of the first clutch 9A and the second clutch 18. Therefore, when the normal operation mode is changed to the fire fighting mode, the mode is temporarily switched to the diesel mode in which the load fluctuation is endured, and the clutch is operated. In the present embodiment, the first clutch 9A and the third clutch 9B are slip clutches, and the clutch can be gradually opened from the closed state, and therefore the clutch can be opened while the gas mode is maintained.

Next, the operation is switched from the diesel mode to the gas mode operation by the first marine propulsion device 20A on the port side (S105), and the mode is switched to the fire fighting mode (S106). Then, the rotation speeds of the right and left

twin engines

3A and 3B are increased. Then, in the fire fighting mode, the fire pump 11 of the fire fighting device 6 is driven by the engine 3A on the port side, and the seawater sucked up from the sea is sprayed through the water spray nozzle 6 a. At the same time, the ship 1 is propelled by driving the starboard propeller 5B with the starboard engine 3B.

Here, although the ship 1 receives a reaction force in the direction of retreating due to the water jet of the fire pump 11, the reaction force is cancelled and the ship 1 stays at the stop position because the propulsion device 5B is driven to advance by the second ship propulsion device 20B on the starboard side. Thus, fire extinguishing activities are performed in the fire fighting mode. The starboard engine 3B does not switch to the fire pump, but the starboard third clutch 9B also opens and closes together with the port in order to balance thrust forces of the port and the starboard. The opening and closing operation of the third clutch 9B may be omitted.

b) Switching step from fire fighting mode to normal operation mode

In the flowchart shown in fig. 6, when the fire extinguishing activity in the fire fighting mode is ended (S107), the ship 1 is switched from the fire fighting mode to the normal operation mode. In this case, the rotation speed of the right and left

twin engines

3A, 3B is reduced to an idle operation state (S108). Then, the third clutch 9B of the second marine propulsion device 20B on the starboard side is set to on. A switching command to switch to the normal operation mode is output (S109).

In the gas mode, when the fire fighting device 6 is switched to the propulsion device 5A, the load may suddenly change, and a fire, a knocking, or the like may occur. Therefore, by temporarily switching to the diesel mode and performing the switching operation of opening and closing the first clutch 9A and the second clutch 18, it is possible to cope with the load variation.

Next, the engine 3A of the first marine propulsion device 20A on the port side is switched from the gas mode operation to the diesel mode operation by the control device 22 (S110). Then, the second clutch 18 on the port side is opened, and the first clutch 9A and the third clutch 9B on the port and starboard sides are closed (S111). The first marine propulsion device 20A on the port side is switched from the diesel mode operation to the gas mode operation (S112), and is set to the normal operation mode together with the second marine propulsion device 20B on the starboard side (S113).

The operation of the engine 3A in the gas mode is susceptible to load fluctuations, and may be hindered from smooth operation of the engine 3A by interference caused by the opening and closing operations of the first clutch 9A and the second clutch 18. Therefore, when the fire fighting mode is shifted to the normal operation mode, the mode is shifted to the diesel mode that is resistant to load fluctuations, and the clutch is opened and closed.

Then, the normal operation mode is performed by increasing the rotation speed of the

engines

3A, 3B of the first and second

ship propulsion devices

20A, 20B on the port and starboard sides, driving the

propellers

5A, 5B of the

propulsion devices

5A, 5B on the port and starboard sides, and propelling the ship 1.

B) Second embodiment

The steps for the case of a transition to diesel mode in the vessel 1 with only a unidirectional transition are described along with fig. 7. In such a case, the load on the fire pump 11 in the fire fighting device 6 is preferably small. That is, in the present second embodiment, the ship 1 does not pass through the diesel mode when switching from the normal operation mode to the fire fighting mode, but passes through the diesel mode when transitioning from the fire fighting mode to the normal operation mode.

a) And switching from the normal operation mode to the fire fighting mode.

In the normal operation mode of the ship 1, the first clutch 9A and the third clutch 9B of the first and second

ship propulsion devices

20A and 20B on the port side are closed, and the second clutch 18 on the port side is opened, so that the

engines

3A and 3B on the port side are operated in the gas mode (S200).

From this state, the rotational speeds of the

engines

3A, 3B of the first and second

marine propulsion devices

20A, 20B on the port and starboard sides are reduced to the idle operation state (S201). Then, the first clutch 9A and the third clutch 9B of the first and second

marine propulsion devices

20A and 20B on the port and starboard sides are opened.

Next, a switching command for switching from the normal operation mode to the fire fighting mode is output to the control device 22 (S202). In such a case, since the load on the fire pump 11 (or other working equipment driven by the engine 3A) is small, the engine 3A of the first marine propulsion device 20A on the port side is not switched to the diesel mode operation and the gas mode operation is maintained by the control device 22.

The third clutch 9B of the second marine propulsion device 20B on the starboard side is closed, and the second clutch 18 on the port side is closed (S203). In this way, in the gas mode, the normal operation mode can be switched to the fire mode (S204). Then, the rotation speeds of the right and left

twin engines

3A and 3B are increased.

In the fire fighting mode, the engine 3A of the first marine propulsion device 20A on the port side drives the fire pump 11 of the fire fighting device 6 to discharge seawater. On the other hand, the second ship propulsion device 20B on the starboard propels the ship 1 by driving the propeller 5B of the propulsion device 5B on the starboard with the engine 3B.

The ship 1 receives a reaction force and a load in the direction of retreating by the water jet of the fire pump 11, but the reaction force is cancelled and the ship 1 stays at the stop position because the propulsion device 5B is advanced by the second ship propulsion device 20B on the starboard side. Thus, fire extinguishing activities are performed in the fire fighting mode.

b) And switching from the fire fighting mode to the normal operation mode.

The operation method in this state is the same as the method shown in a) b) described above, and will be described along the flowchart shown in fig. 6.

In the ship 1, in the fire fighting mode (S107), the first clutch 9A of the first ship propulsion device 20A on the port side is opened, and the second clutch 18 is closed. The third clutch 9B of the second marine propulsion device 20B on the starboard side is closed. In this state, the fire pump 11 of the fire fighting device 6 is driven by the engine 3A on the port side to spray water. The propeller 5B of the second marine propulsion device 20B is driven by the starboard engine 3B to propel the ship 1.

When the fire fighting mode is switched, the rotational speeds of the

engines

3A, 3B of the first and second

marine propulsion devices

20A, 20B on the port and starboard sides are reduced to idle operation (S108).

Next, the third clutch 9B on the starboard side is opened. Then, a command to switch the ship 1 from the fire fighting mode to the normal operation mode is output to the control device 22 (S109). Thereby, in the first marine propulsion device 20A on the port side, the engine 3A is switched from the gas mode operation to the diesel mode operation (S110).

In the first ship propulsion device 20A on the port side, the second clutch 18 is opened. In the first and second

marine propulsion devices

20A, 20B on the port and starboard sides, the first clutch 9A and the third clutch 9B are closed (S111). Then, the first marine propulsion device 20A on the port side is switched from the diesel mode operation to the gas mode operation (S112).

Next, the rotation speeds of the

engines

3A, 3B of the first and second

marine propulsion devices

20A, 20B on the port and starboard sides are increased. Then, in the normal operation mode, the

propellers

5A, 5B of the right and left twin-

side propulsion devices

5A, 5B are driven to propel the ship 1 (S113).

In this way, the switching operation between the gas mode and the diesel mode in the case where the load on the fire-fighting device 6 is large or small is controlled.

C) Automatic deceleration control

In the normal operation state of the ship 1, the working equipment driving state such as the fire fighting mode, and the like, it is necessary to avoid overload of the output values of the propulsion equipment

side output sensors

14A and 14B and the working equipment side output sensor 19 by the dual-

fuel engines

3A and 3B, and to define the ship-level regulation by the ship-level turbines. For example, if the output measurement value of each propulsion unit-

side output sensor

14A, 14B by the

engine

3A, 3B becomes 80%, the control unit 22 sends an alarm, and if the output measurement value does not decrease to 95% for 30 seconds after becoming 100% or more, it is regarded that the state of 100% continues. In such a case, for example, in the ship-level regulation defined by ABS (usa), when the state where the output of the engine 3A is 95% or more continues for 30 seconds,if the override button is not pressed within 5 seconds after that, the rotational speed of the

engines

3A and 3B is forcibly reduced. Suppose that if the preset deceleration value is set as the specified value Xmin^-1Then, the rotational speed of the

engines

3A, 3B is forcibly decelerated to Xmin^-1Until now.

In general, although the output measurement value of the working device side output sensor 19 on the fire protection device 6 side is small and will not be 100%, the

propulsion devices

5A and 5B may excessively drive and propel the ship in order to avoid danger during operation of the ship 1, and thus an excessive output may be applied to the

engines

3A and 3B. In such a case, the engine 3 is protected by the automatic deceleration control.

Next, an example of automatic deceleration control based on the ship-level rule will be described with reference to fig. 8.

In the normal operation mode (S300), during propulsion of the

propulsion devices

5A, 5B, for example, in order to avoid danger, there may be a case where the measured values of the outputs of the propulsion device-

side output sensors

14A, 14B by the dual-

fuel engines

3A, 3B exceed a predetermined upper limit value (reference value) (S301). In this case, the rotation speed is reduced at a predetermined rate so that the output measurement value of the engine 3A becomes equal to or less than the upper limit value (S302).

The upper limit value of the automatic deceleration control may be set only by the output value of the engine 3A of the first marine propulsion device 20A on the port side where the fire fighting device 6 is provided, or only by the output value of the engine 3B of the second marine propulsion device 20B without a fire pump. Alternatively, the total output value of both the port and

starboard engines

3A and 3B may be set. Which one is selected is appropriately set as necessary.

According to the power system of the ship 1 according to the present embodiment, the dual-

fuel engines

3A and 3B that can be operated by switching between the gas mode and the diesel mode are used. In the gas mode, in order to prevent knocking or misfiring, it is necessary to control the ratio of the amounts of fuel gas and air more accurately, and it is effective to measure the outputs of the

engines

3A and 3B in real time by the propulsion unit

side output sensors

14A and 14B and control the

engines

3A and 3B accordingly.

As described above, according to the power train of the ship according to the present embodiment, the propulsion unit-

side output sensors

14A and 14B on the

propulsion units

5A and 5B side and the work unit-side output sensor 19 are provided between the

engines

3A and 3B and the first clutch 9A and the third clutch 9B, and between the engine 3A and the second clutch 18, respectively, so that the actual output of the engine 3A including the loss due to the resistance of the transmission system, the clutch, and the like can be measured more accurately. Even when the first clutch 9A and the second clutch 18 are in the open state, the output including the resistance can be measured.

Therefore, even in the gas engine mode using gas fuel, the

engine

3A, 3B can be strictly controlled by detecting the output measurement values of the

engine

3A, 3B by the propulsion system-

side output sensor

14A, 14B and the work machine-side output sensor 19.

Further, during the operation in the gas mode of the ship 1, when the driving state of the propulsion device 5A and the state of driving the fire pump 11 are changed in both directions, the gas mode is temporarily switched to the load fluctuation tolerant diesel mode, and the opening/closing switching operation of the first clutch 9A and the second clutch 18 is performed, so that the engine 3A can be smoothly operated without being affected by the load fluctuation, while suppressing the disturbance caused by the opening/closing of the first clutch 9A and the second clutch 18.

When the load generated by the fire pump is relatively small, the disturbance when the second clutch 18 on the fire pump 11 side is closed is also relatively small, and therefore, the transition to the fire fighting device 6 may be omitted depending on the conditions.

Further, when the measured values of the outputs of propulsion device-

side output sensors

14A and 14B or the measured value of the output of work device-side output sensor 19 exceed a predetermined upper limit value during automatic deceleration control, knocking, misfire, and the like can be prevented by performing control to forcibly reduce the rotation speeds of both

engines

3A and 3B.

In the case of the dual-fuel engine 3A on the port side, even when the second clutch 18 on the fire fighting device 6 side is opened or the first clutch 9A on the propulsion device 5A side is opened, a certain degree of mechanical loss remains on the fire pump 11 side or the propulsion device 5A side. Therefore, by obtaining the sum of the output value from the propulsion device-side output sensor 14A and the output value from the working device-side output sensor 19 on the fire fighting device 6 side, a more accurate output value of the engine 3A can be obtained, and the engine 3A can be controlled with high accuracy.

Further, based on the sum of the output values of the propulsion device-side output sensor 14A and the working device-side output sensor 19, the automatic deceleration control for reducing the rotation speed of the engine 3A can be performed.

Further, according to the ship 1 having the fire fighting device 6 according to the present embodiment, since the first ship propulsion device 20A including the engine 3A and the second ship propulsion device 20B including the engine 3B, which are two in total, are provided in parallel on both the right and left sides, when the fire pump 11 of the fire fighting device 6 is driven by one of the dual-fuel engines 3A to spray water, the other dual-fuel engine 3B propels the ship, and the ship 1 is prevented from backing up by the reaction force of the driving load of the fire pump 11, thereby enabling fire extinguishing activities.

The power system of the ship 1 according to the present invention is not limited to the above-described embodiment, and can be appropriately changed or replaced without departing from the scope of the present invention. In the following, although modifications and the like of the present invention are described, the same reference numerals are used for the same or similar parts and components and the like as those described in the above embodiments, and the description thereof is omitted.

In an embodiment of the invention, a power system of the following vessel 1 is used, namely: the first marine propulsion device 20A and the second marine propulsion device 20B are arranged on the port side and the starboard side of the ship 1, and the fire protection device 6 is provided as a working device in the first marine propulsion device 20A, so that one of the gas mode and the diesel mode is selectively operated.

However, the above-described invention is merely an embodiment of the present invention, and the present invention is not limited to such a configuration. The concept of the present invention can be applied to any configuration of the present invention as long as the output of the dual-fuel engine 3 is used for driving a working device other than the propulsion device 5.

For example, the working device is not limited to the fire fighting device 6 including the fire pump 11, and working devices including pumps for other purposes, loading and unloading machines such as cranes, and various machines mounted on the vessel 1 and driven by the main engine that propels the vessel 1 may be used.

In the power system of the ship 1 according to the present invention, the control of the dual-fuel engine 3A may be performed based on one or a total of the output measurement value of the propulsion system-side output sensor 14A and the output measurement value of the work device-side output sensor 19.

Alternatively, the control of the bi-fuel engine 3A may be performed based on the output measurement value of the propulsion device-side output sensor 14A in a state where the first clutch 9A is closed, or the control of the bi-fuel engine 3A may be performed based on the output measurement value of the working device-side output sensor 19 in a state where the second clutch 18 is closed.

The power train of the vessel 1 according to the present invention is not limited to a configuration in which two

propulsion devices

5A and 5B are provided on the port side and the starboard side, and one of them is provided with a working device such as a fire fighting device 6. For example, one propulsion device 5 may be provided, and a working device such as a fire fighting device 6 may be provided by providing a drive shaft 17 to the dual fuel engine 3. Alternatively, three or more propulsion devices 5 may be provided, and a working device such as a fire fighting device may be attached to the engine 3 provided with one or two or more propulsion devices 5.

Possibility of industrial utilization

The present invention is configured such that a propulsion device is connected to an engine that can use at least gaseous fuel as a main fuel via a first clutch, and a working device such as a fire fighting device is connected to the engine via a second clutch, and a propulsion device-side output sensor is provided between the engine and the first clutch, and a working device-side output sensor is provided between the engine and the second clutch. The first clutch is closed and the second clutch is opened to drive the propulsion device, and the first clutch is opened and the second clutch is closed to drive the working device. Further, a power system of a ship capable of driving and controlling a working device in a gas mode is provided by measuring an output of an engine mainly using a gas fuel by a propulsion device side output sensor and a working device side output sensor to control driving of the engine.

Description of the reference numerals

1 Ship

3. 3A, 3B double fuel engine (engine)

5. 5A, 5B propulsion unit

6 fire-fighting device

9A first clutch

9B third clutch

11 fire pump

13A, 13B propulsion shaft

14. 14A, 14B propulsion unit side output sensor

15. 15A, 15B rotational speed sensor

17 drive shaft

18 second clutch

19 working device side output sensor

22 control the device.

Claims

1. A power system for a marine vessel, comprising:

an engine capable of using a gaseous fuel as a main fuel;

a propulsion device connected to the engine via a first clutch and driven;

a propulsion device-side output sensor provided between the engine and the first clutch;

a working device connected to and driven by the engine via a second clutch; and

a working device side output sensor provided between the engine and the second clutch,

in the operation mode in which the gaseous fuel is the main fuel, when the state of driving the propulsion device is changed to the state of driving the working device,

the operation mode is switched from the operation mode using the gas fuel as the main fuel to the operation mode using the liquid fuel as the main fuel, one of the first clutch and the second clutch is opened and the other is closed, and then the operation mode is returned from the operation mode using the liquid fuel as the main fuel to the operation mode using the gas fuel as the main fuel.

2. The power system of a marine vessel according to claim 1,

the working device is a fire fighting device for spraying water.

3. The power system of a marine vessel according to claim 1 or 2,

the power system of the vessel includes a control device that closes the first clutch and opens the second clutch to drive the propulsion device, opens the first clutch and closes the second clutch to drive the working device.

4. The power system of a marine vessel according to any one of claims 1 to 3,

the engine is controlled based on a sum of an output measurement value based on the propulsion device-side output sensor and an output measurement value based on the work device-side output sensor.

5. The power system of a marine vessel according to any one of claims 1 to 4,

the control unit performs control to reduce the rotation speed of the engine when an output measurement value based on the propulsion device-side output sensor and/or an output measurement value based on the work device-side output sensor exceeds an upper limit value.

6. The power system of a marine vessel according to any one of claims 1 to 5,

the propulsion device-side output sensor and the work device-side output sensor are torque sensors that measure torque actually applied to a propulsion shaft of the engine.

7. A power system for a marine vessel, comprising:

an engine capable of using a gaseous fuel as a main fuel;

a propulsion device connected to the engine via a first clutch and driven;

a working device connected to and driven by the engine via a second clutch; and

in the operation mode in which the gaseous fuel is the main fuel, when the state of the working device is changed from the state of driving the working device to the state of driving the propulsion device,

8. A power system for a marine vessel, comprising:

an engine capable of using a gaseous fuel as a main fuel;

a propulsion device connected to the engine via a first clutch and driven;

a working device connected to and driven by the engine via a second clutch;

a working device side output sensor provided between the engine and the second clutch; and

a control device that turns off the first clutch and turns on the second clutch to drive the propulsion device, turns on the first clutch and turns off the second clutch to drive the working device,

the control device includes:

a diesel mode switching means for switching from a gas mode in which a gas fuel is used as a main fuel to a diesel mode in which a liquid fuel is used as a main fuel in order to perform an operation of opening one of the first clutch and the second clutch and closing the other of the first clutch and the second clutch; and

and a gas mode switching unit configured to switch from the diesel mode to the gas mode after an operation of opening one of the first clutch and the second clutch and an operation of closing the other clutch are completed.

9. A power system for a ship, comprising a plurality of engines capable of using a gaseous fuel as a main fuel,

on an engine side comprising:

a propulsion device connected to the engine via a first clutch and driven;

a working device connected to and driven by the engine via a second clutch;

on the other engine side, the engine comprises:

another propulsion device connected to the another engine via a third clutch and driven; and

a second propulsion device-side output sensor provided between the second clutch and the second engine,

by the control device, when the first clutch is opened and the second clutch is closed to drive the working device, the third clutch is closed to drive the other propulsion device.